Lighting fixture



Nov. 23, 1943. H, VACHA LIGHTING FIXTURE Filed Dec. 3, 1941 2 Sheets-Sheet l INVENTQR NORMAN H. VACHA ATTORNEY-5 LIGHTING FIXTURE Filed Dec. 3, 1941 2 Sheets-Sheet 2 20' 2/ a a 4 l 2'0 INVENTOR NORMAN H. VACHA v Y W ATTORNEYS Patented Nov. 23, 1943 LIGHTING FIXTURE.

Norman H. Vacha, Cleveland, Ohio, assignor to John C. Virden Company, Cleveland, Ohio, a

corporation of Ohio Application December 3, 1941, Serial No. 421,467

4 Claims. (01. 240-78) This invention relates to an improvement in lighting fixtures. More particularly, this invention relates to a fluorescent lighting fixture which requires a minimum of time and labor for maintenance and is, therefore, especially suited for use in industrial plants or similar locations where the presence of dust and dirt is likely to reduce the efficiency of a fluorescent lamp.

Due to its superior light distribution and economy of current, fluorescent lighting is being adopted widely in industrial plants and similar locations where a high level of illumination is desirable. A primary objection to fluorescent lighting fixtures in locations where appreciable amounts of dust and grime are present is that maintenance costs, and particularly the dusting of the tubes and the cleaning of reflectors, may offset the operating economy. An apparently inherent characteristic of a fluorescent tube is its low light intensity per unit of area of its surface, as compared, for example, with an incandescent bulb. Thus, both fluorescent tubes and their reflee-tors must have a large surface area to produce a large amount of light. As a result, small amounts of dust collected on the surfaces of fluorescent tubes and their reflectors will seriously reduce the efficiency of fluorescent lighting fixtures. Therefore, to obtain the optimum amount of light from a fluorescent lighting fixture, the fixture must be cleaned thoroughly and frequently.

In the fluorescent lighting fixtures available heretofore, it was necessary to remove one or more fluorescent tubes before the reflectors could be removed for washing. This operation was time consuming and resulted in the breakage of the fluorescent tubes. Furthermore, such fixtures required that the light be switched off while a fixture was being cleaned. It is an object of this invention to provide a fluorescent lighting fixture with a reflector which may be quickly and readily removed for cleaning without removing or switching off the fluorescent tubes. The advantages of my fixture are that a great savings of time in maintenance is afforded, breakage of tubes during cleaning is reduced to a minimum, and work on machines illuminated by my fixture is not necessarily stopped during cleaning of the reflector and tubes.

parts of my fluorescent lighting fixture, except the tubesockets, may be inspected and replaced after the fixture is installed without removing or otherwise handling the tubes.

It is also an object of my invention to provide a simple and inexpensive but strong fixture which will protect the fragile ceramic tube sockets and cover the ballast, wiring, and starting switch sockets. A still further object of my invention is to provide a fluorescent lighting fixture which may be easily installed at a wide range of angles for directional control of the light. Fixtures made according to my invention may also be readily fastened end-tc-end for continuous line lighting.

Other objects and, advantages of my invention will be apparent from the disclosure in the following specification, claims, and drawings in which:

Fig. 1 is a cross-sectional view taken along the line I--l of Fig. 2;

Fig. 2 is an isometric view of my fixture, viewed from above;

Fig. 3 is an isometric view of my fixture hung in a tilted position and viewed from below; and

Fig. 4 is a fragmentary longitudinal section showing two of my fixtures joined end-to-end.

In the drawings, in which like reference characters refer to like parts, the fixture is comprised of a chassis I0 and removable reflector II. The chassis I0 is comprised of a longitudinally extending shallow channel member I2, preferably provided with flanges I3, and end members I4 secured to each end of the channel I2. The end members I4 comprise a lower laterally extending box portion I5, provided with a removable cover I6, and an upper hanger plate portion II provided with a plurality of hook holes I8. The back of the box portion I5 is provided with a boss IE! to which the channel I2 is secured.

Each chassis I0 carries two fluorescent tubes 20 mounted in sockets 2I located in the box por- .tions I5 of the end members I4. The sockets M are preferably located below and to each side of the channel I2. Each box portion I5 is provided with an opening 32 to permit wiring to be led from the channel I2 to the sockets 2I.

The channel I2 carries the ballast 22 for the tubes 20 midway between the end members I4, the ballast 22 being secured in the channel I2 by means of stud bolts 43 located centrally of the channel I2. The ballast 22 is preferably of a properly phased high power factor type to minimize the strobosoopic effect of the tubes 20. A ballast housing 23 is removably secured to the channel I2 by means of the cap screws 24 so that the ballast 22 is normally protected from dust.

Preferably adjacent the end members !4, two central openings are punched in the bottom of the channel l2 to receive the starting switches 25. Above each opening is a starting switch socket 26 removably secured to the channel l2. Wiring (not shown for simplicity of illustration) is carried in the channel I2 to connect the ballast, starting switches and tube sockets. All metal elements in the chassis Ill and housing 23 are electrically connected and the power cable 2'1 connecting the ballast 22 to the source of power preferably has a third ground wire con nected to the chassis It! so that the chassis is thus grounded.

The reflector II is a trough-shaped member provided with a baked porcelain or similar refleeting finish on its inner surface. The reflector extends from one end member to. the other end member, sufiicient space being allowed adjacent at least one end member to permit the cable 21' to extend from the. channell2 to the. sourceof power Midway between the ends of the reflector an-opening, 28 is punched in the central portion of the reflectorto permit. the, refiectorto fit down over the. ballasthousing and reston the flanges E3 of the. channel l2. Any suitable releasably securing meansmay be employed to secure the reflector H to the chassis, Id. Avery simple and effective means shown in Figs. 1 and 2 comprises several catches 29, pivotally mountedon the sloping ends of the ballast housing Z3.v The catches 23. are preferabl somewhat resilient sothatthey are sprung slightly when they are turned toengage the. reflector H. The coating of the. outer surface oithe reflector It is preferab y thin or brittle enoughso that itv will be scratched through by the catch 29 and thus be grounded :to. the chassis Iii. Since the innersurfaceof the. reflector may insulate the reflector from the chane nel {2, unless the reflector ll, usually ctmetal, is thus grounded, a dangerous conditioninay ,be created due'to currents induced from the wiring in the channel, l2.

My fixtureis readily installed for. use by hooking each 01" the, hanger plates [1 to, a drop chain til by means of the double hooks at. If the fixture is to be. hung in a horizontal. position, a showninFig. 2, the hooks 35 are simply passed through the, central holes. of the arcuately arranged hock holes 16., If the fixture is to be hung in a tilted Position, each of the, hooks}! are passed through a laterally displacedhook hole, as shown in, Fig. 3. If vibrations tend to cause the fixture to, swing, the hanger plates may be bolted to a rigidly mo nted bracket, the arouately arranged hook holes {3 permitting the fixture to be fastened at awide range of angles.

If it is desired to, mount a plurality of fixtures so that a continuous lineof; lighting is secured, the cover plates it are removed from the box portions 55 of adjacent ends of a plurality of, chassis by removing the short bolts 33 which hold the cover plates it in the box portions 65. The

adjacent end members It, are then held in abut.- ment by a long, bolt 3:; substituted for the short bolts 33, as shown in Fig. 4. Suitable power cables for'connecting; the aligned fixtures may be passed through the openings 32 in the adjacent end members. When the end members arosecured together as shown in Fig. 4, they'nray be prevented from twisting with respect to each other by pinning through adjacent hook holes or providing the end members with suitable interfitting keys. The contacting vertical surfaces of the, abutting end members tend to prevent the joined fixtures from sagging, but the joint is preferably supported, as by the chain 30 and hook 3! shown in Fig. 4.

After the fixture is installed, it is easily cleaned by simply turning the catches 29 and lifting on the reflector II for washing. Because the tubes 20 are spaced laterally from the channel i2, any dust which may collect on the tubes may be easily brushed ofi when the reflector is removed. After the reflector is washed, it is quickly replaced by simply dropping it over the ballast housing and turning the catches 29. Thus, my fixture may be cleaned without removing the tube from the fixture. Consequently, breakage of the tube, due to handling, is reduced to a minimum and is usually eliminated entirely.

When using fluorescent lighting fixtures, the tubes must be replaced from time to time and the starting switches must also be replaced. The tubes are removed from the fixture by employing the conventional button typ sockets which permit the'tube to be removed by twisting it in the socket and then remoyingitlaterally. By locating the starting switch sockets centrally of the channel I2 and providing an opening in the channel, the startingswitch 25 may be inserted without removing the reflector H or either of the tubes. Thus, the reflector H tubes 20, and starting switches 25 may each be removedfrom the fixture without disturbing any other element or part of the fixture. 7 It is an especial advantage that the reflector H maybe removed for cleaning without switching off the tubes 20, since this usually allows the maintenance crew to clean the fixture without seriously interrupting the work lighted by the fixture.

A11 wiring in my fixture is covered and concealable when the reflector H is in place, since the, reflector also. serves as a cover for the channel l2. With the reflector removed, however, all wiring exposed for inspection. In fluorescent lighting equipment, it is seldom that the ballast or starting switch sockets must be replaced but in my fixture .even these elements may be replaced without takingdown the fixture or removing the tubes. To replace either thestarting switch sockets or the ballast, the lights are switched, oil, of course, and the reflector is removed. A starting switch socket is then replaced by simply removing the defective socket from the upstanding flange in the channelto which it is secured and securin a new socket in place. The ballast 22' is removed by loosening the cap screws 24 to permit the ballast housing 23 to be removed. The ballast 22 is then removed by loosening the stud bolts 43.

In many fluorescent fixtures the ceramic button type tube sockets are exposed so that blows on the end of the fixtu e, such as when the end of the fixture is hit by a ladder being carried by afworkman, will break the tubes and sockets or at least throw the sockets out of line. In my fixture thev tubes and sockets are protected from endblows by the end members M.

Th foregoing is a description of a preferred form of'my invention. Obviously, this disclosed embodiment may be modified either in whole or iii-part without departing from th spirit and scope of this invention. Therefore, my invention. is n t tob limited to. the embod men di closedor for the spe ific uses described. but is mited only by the appended claims.-

What is cla med is:

A a anufacture, a fluorescent lighting fixture mprising,- a longitudinally I extending channel, a fluorescent ballast and ballast housing removably secured in said channel, end members integral with each end of said channel, fluorescent tube sockets carried by said end members, fluorescent tubes being removably mounted in said sockets, said tubes being disposed parallel to but laterally spaced from said channel, wiring connecting said ballast and said tubes lying within said channel, a reflector for said tubes fitted over said ballast housing and covering said wiring in said channel, and means for removably securing said reflector to said channel, said means constituting the sole means for preventing said reflector from being removed from said channel.

2. In a fluorescent lighting fixture as described in claim 1, a starter switch for each fluorescent tube, starter switch sockets mounted in said channel, said starter switch socket, fluorescent tube sockets, and reflector securing means being each so arranged in the fixture and so constructed that said starter switches, fluorescent tubes, and said reflector each may be removed from the fixture independently of any other element in the fixture.

3. A fixture as defined in claim 1 in which said removable securing means are mounted on said ballast housing and, when engaging said reflector, ground said reflector to said housing.

4. AS a manufacture, a normally dependent fluorescent lighting fixture comprising a chassis, a longitudinally extending reflector normally resting on said chassis, a pair of fluorescent tubes upported below said chassis, end members connected to said chassis beyond the longitudinal ends of said reflector, said end members being adapted to be connected to supporting means, and means for removably securing said reflector to said chassis,whereby said reflector may be removed from said chassis independently of any other element in the fixture, said end members comprising a box portion, fluorescent tube sockets mounted in said box portion, a removable cover for said box portion to protect said sockets, and means to secure said cover in said box portion or to secure said box portion to a similar box portion of another fixture.

NORMAN H. VACHA. 

